The invention is based on an optical connection for the exchange of data between devices and a connection unit for the exchange of optical signals of the type described in the independent claims. A large number of individual devices and components are required for the most widely differing applications, which are fitted into installation units such as racks. This large number of components and devices must in general communicate with one another and exchange information and signals. An example of this is a digital switching station, in which, for example, up to 40 individual installation units may be located and must be connected to one another. For the installation of the different units it is of significance which devices must communicate with one another, depending on their individual tasks. Accordingly, the arrangement of the individual installation units within an area is a logistics problem. The data connections are, in this situation, created by the individual installation units, the individual racks, via optical fibre or wire connections. Positioning in relation to one another is therefore established in such a way that it is not possible simply to unplug and change the individual connections.
It is known in the state of the art, for example from U.S. Pat. No. 5,091,985, to connect individual devices with one another in a rack optically by means of a waveguide structure. In this situation, it is assumed that high data rates can be transferred very flexibly by optical communications. The individual components of a rack in this situation comprise a transmitter-receiver structure, which creates the image of the information on a waveguide by means of an optical imaging device, so that all the devices connected to this waveguide can receive the information from the waveguide. This structure serves to provide communication within a rack.
By contrast, the optical connection in accordance with the invention for the exchange of data between devices, which are installed in separate installation units in an enclosed space, has the advantage that the devices in the installation units communicate with one another by means of optical signals, where the optical signals overcome the distance between the installation units. As a result, a wireless connection is achieved between individual racks, which can be erected in the area as an island solution, and offers free access to optical connections with one another. For such an optical connection, light is advantageously transferred between installation units, so that it is only necessary to ensure that there is no interruption of the light path and hence of the information flow. In other words, the optical signals are transmitted wirelessly between the installation units, i.e., without employing cables, wires, etc. More specifically, the optical signals are transmitted wirelessly between connection units that are arranged on top of the installation units. In the present invention as disclosed and as claimed, the term xe2x80x9cwireless optical signalsxe2x80x9d designates optical signals that are transmitted wirelessly, i.e., optical signals that are transmitted over a wireless connection.
The connection unit in accordance with the invention, for the exchange of optical signals, has the advantage that it includes at least one transmitter and at least one receiver, which are connected to a demultiplexer and a multiplexer. As a result, a large number of channels for the transfer of data are advantageously opened, so that the requirement for high data rates and for different data channels are fulfilled.
The quality of the transfer is advantageously monitored by a special calibration transmitter and a calibration receiver. As a result, the system can be automatically monitored and a data transfer free of complications can be assured. The synchronisation of the signals is advantageously ensured by means of a separate system clock, the signals of which are transmitted and received with the calibration signal and matched to one another. The adjustment of the connection units to one another is effected during installation of the units, in that the transmitter and receiver units are mechanically tuned to one another. To do this, the connection units are gimbal-mounted in the installation units, and can be pushed against one another and adjusted in a simple manner. The automatic monitoring for this calibration signal allows for an indication as to whether any readjustment should be undertaken.